An unconscious horse, lying on its back with a tube coming out of its mouth, is pushed on a trolley at high speed. He has just had an ultrasound scan on his leg, and is heading for the operating theatre.

"They want to operate now, before he comes round, rather than having to anaesthetise him twice," says Polly Compston, a vet at Newmarket equine hospital Rossdales. Supported by the Margaret Giffen Trust, Compston is researching the benefits of repairing fractures under a local anaesthetic.

As a graduate, she did work experience in Morocco with Spana, a charity for working animals, which helped her identify ways in which she could take her veterinary career forward. Many of Rossdales' clients are valuable racehorses, with a smattering of three-day eventers and dressage horses – a far cry from the donkeys, mules and horses she came across with Spana.

She volunteered as a vet in Marrakesh for a month. Although she was already fully qualified, Compston says the work experience helped her to home in on what she really wanted to do. "It made me a better vet. Here we have 20 experienced nurses, the horses are well handled and we have all the equipment and drugs we could possibly need. There, the donkeys and mules weren't easy to handle and it was difficult to do many things we take for granted here, like take an x-ray."

Compston is considering a PhD in equine epidemiology, but is sure she will end up travelling and working as a vet again. "Spana really focused me on the working animal side of things – how strongly I felt about being able to help people by helping their animals."

Spana sends only two volunteer vets to Marrakesh at a time, although the vets can move on to one of eight other centres in Morocco, making room for new recruits. Jane Harry, Spana's veterinary programme adviser, says: "They all start in Marrakesh where the [resident] vets speak good English and it's usually very safe. Then if we're happy they are going to cope with the language barrier and they are not too timid, they'll move on to other areas."

The charity provides accommodation, but volunteers pay for their own flights, insurance and food. It helps to speak French and have a diplomatic nature, and volunteers must have vaccinations for rabies and tetanus.

They are supervised until the resident vets are confident about the volunteers' ability, as they will come across conditions they may never have seen in the UK, such as respiratory and eye diseases, rabies, tetanus, mange and wounds, some caused by bad harnessing but also "gaping flesh wounds" incurred in accidents. Harry says many of the animals suffer from colic, which can quickly prove fatal for equines: "You'll see two or three cases every day, partly because the animals forage on rubbish sites and eat plastic bags, partly from internal parasites, and often because of the limited supply of water."

Vets working in Morocco have to do their own lab work and rely on their own examinations. "Resource-wise they learn to think laterally," Harry says.

Such experience can make all the difference when it comes to applying for jobs. "As a potential employer, when people come out of uni there's not much to differentiate between them. But if they have taken the initiative to do this, they'll be a lot more confident and practised in their clinical skills," Harry says.

Kelly Harrison, who graduated this year, spent three weeks in Morocco. "I didn't learn much theory because I had just graduated and have a good UK training, but the practical experience was fantastic. In the UK horses have such a high value it's difficult to let students develop practical skills. But in Morocco they have a more relaxed attitude. I saw just two horses with colic in the whole of vet school, but I dealt with 20 in my three weeks in Morocco and I didn't have a single problem. It's great for your confidence."

Harrison is now on an 18-month contract working for an equine hospital in Gloucestershire. She says: "The time with Spana means that when the vets here ask me if I am happy to carry out a procedure, I can say yes."